Most breast cancers in men are ductal carcinomas. Ductal means the cancer started in the milk pipes of the breast, called ducts. These cancers are usually invasive because they start inside the duct and then break through the wall of the duct, growing into the normal surrounding breast tissue.
Cancer Registry of Norway shows that the nationwide Norwegian mammographic screening programme reduces breast cancer mortality by 43 % among attendees compared to non-attendees. This is a much larger effect than expected. The results are based on a large epidemiological study using data from about 700 000 Norwegian women aged 50-69.